Polysilicon is a material, which may be used in the manufacture of solar panels. Polysilicon production has grown tremendously over the last few years due to the increasing costs associated with energy production. Many state and local governments have mandated that a certain percentage of the energy produced within their respective jurisdictions be from a renewable source. Electricity generated via solar panels is classified as a renewable energy source in these regulations. The U.S. federal government has offered extensive tax credits to promote investment into polysilicon and solar panel production.
Along with other compounds and materials, polysilicon production requires anhydrous hydrogen chloride gas, which can be generated by combining chlorine and hydrogen. More particularly, typically chlorine and hydrogen are combined in a polysilicon plant to generate anhydrous hydrogen chloride gas. This hydrogen chloride gas, along with metallurgical-grade silicon, is then fed to a process plant, where polysilicon and other chemicals are generated. Waste streams, which need to be properly disposed, are typically generated during this process. Some of these waste streams include chlorine containing compounds.
In some parts of the world, hydrogen chloride and chlorine may be relatively difficult to obtain. Further, transporting hydrogen chloride and chlorine may raise cost, permitting, environmental, and/or health issues. For example, shipping rates for chlorine have nearly tripled over the last few years. Further, U.S. Department of Transportation and other security regulations that require dedicated trains, secure storage areas, and restrictions on shipping toxic inhalation hazard (TIH) chemicals, which include hydrogen chloride and chlorine, through certain areas are impacting the ability to ship these chemicals. Yet further, numerous hydrogen chloride and chlorine production plants in Europe and North America are slated for closure because of environmental regulations, thus further limiting potential chemical supply sources.